/* * Digital I/O driver for Technologic Systems I2C FPGA Core * * Copyright (C) 2015 Technologic Systems * Copyright (C) 2016 Savoir-Faire Linux * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * This program is distributed "as is" WITHOUT ANY WARRANTY of any * kind, whether expressed or implied; without even the implied warranty * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License version 2 for more details. */ #include <linux/gpio/driver.h> #include <linux/i2c.h> #include <linux/of_device.h> #include <linux/module.h> #include <linux/regmap.h> #define DEFAULT_PIN_NUMBER 32 /* * Register bits used by the GPIO device * Some boards, such as TS-7970 do not have a separate input bit */ #define TS4900_GPIO_OE 0x01 #define TS4900_GPIO_OUT 0x02 #define TS4900_GPIO_IN 0x04 #define TS7970_GPIO_IN 0x02 struct ts4900_gpio_priv { struct regmap *regmap; struct gpio_chip gpio_chip; unsigned int input_bit; }; static int ts4900_gpio_get_direction(struct gpio_chip *chip, unsigned int offset) { struct ts4900_gpio_priv *priv = gpiochip_get_data(chip); unsigned int reg; regmap_read(priv->regmap, offset, ®); return !(reg & TS4900_GPIO_OE); } static int ts4900_gpio_direction_input(struct gpio_chip *chip, unsigned int offset) { struct ts4900_gpio_priv *priv = gpiochip_get_data(chip); /* * This will clear the output enable bit, the other bits are * dontcare when this is cleared */ return regmap_write(priv->regmap, offset, 0); } static int ts4900_gpio_direction_output(struct gpio_chip *chip, unsigned int offset, int value) { struct ts4900_gpio_priv *priv = gpiochip_get_data(chip); int ret; if (value) ret = regmap_write(priv->regmap, offset, TS4900_GPIO_OE | TS4900_GPIO_OUT); else ret = regmap_write(priv->regmap, offset, TS4900_GPIO_OE); return ret; } static int ts4900_gpio_get(struct gpio_chip *chip, unsigned int offset) { struct ts4900_gpio_priv *priv = gpiochip_get_data(chip); unsigned int reg; regmap_read(priv->regmap, offset, ®); return !!(reg & priv->input_bit); } static void ts4900_gpio_set(struct gpio_chip *chip, unsigned int offset, int value) { struct ts4900_gpio_priv *priv = gpiochip_get_data(chip); if (value) regmap_update_bits(priv->regmap, offset, TS4900_GPIO_OUT, TS4900_GPIO_OUT); else regmap_update_bits(priv->regmap, offset, TS4900_GPIO_OUT, 0); } static const struct regmap_config ts4900_regmap_config = { .reg_bits = 16, .val_bits = 8, }; static const struct gpio_chip template_chip = { .label = "ts4900-gpio", .owner = THIS_MODULE, .get_direction = ts4900_gpio_get_direction, .direction_input = ts4900_gpio_direction_input, .direction_output = ts4900_gpio_direction_output, .get = ts4900_gpio_get, .set = ts4900_gpio_set, .base = -1, .can_sleep = true, }; static const struct of_device_id ts4900_gpio_of_match_table[] = { { .compatible = "technologic,ts4900-gpio", .data = (void *)TS4900_GPIO_IN, }, { .compatible = "technologic,ts7970-gpio", .data = (void *)TS7970_GPIO_IN, }, { /* sentinel */ }, }; MODULE_DEVICE_TABLE(of, ts4900_gpio_of_match_table); static int ts4900_gpio_probe(struct i2c_client *client, const struct i2c_device_id *id) { const struct of_device_id *match; struct ts4900_gpio_priv *priv; u32 ngpio; int ret; match = of_match_device(ts4900_gpio_of_match_table, &client->dev); if (!match) return -EINVAL; if (of_property_read_u32(client->dev.of_node, "ngpios", &ngpio)) ngpio = DEFAULT_PIN_NUMBER; priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL); if (!priv) return -ENOMEM; priv->gpio_chip = template_chip; priv->gpio_chip.label = "ts4900-gpio"; priv->gpio_chip.ngpio = ngpio; priv->gpio_chip.parent = &client->dev; priv->input_bit = (uintptr_t)match->data; priv->regmap = devm_regmap_init_i2c(client, &ts4900_regmap_config); if (IS_ERR(priv->regmap)) { ret = PTR_ERR(priv->regmap); dev_err(&client->dev, "Failed to allocate register map: %d\n", ret); return ret; } ret = devm_gpiochip_add_data(&client->dev, &priv->gpio_chip, priv); if (ret < 0) { dev_err(&client->dev, "Unable to register gpiochip\n"); return ret; } i2c_set_clientdata(client, priv); return 0; } static const struct i2c_device_id ts4900_gpio_id_table[] = { { "ts4900-gpio", }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(i2c, ts4900_gpio_id_table); static struct i2c_driver ts4900_gpio_driver = { .driver = { .name = "ts4900-gpio", .of_match_table = ts4900_gpio_of_match_table, }, .probe = ts4900_gpio_probe, .id_table = ts4900_gpio_id_table, }; module_i2c_driver(ts4900_gpio_driver); MODULE_AUTHOR("Technologic Systems"); MODULE_DESCRIPTION("GPIO interface for Technologic Systems I2C-FPGA core"); MODULE_LICENSE("GPL");